Electric lamp holder



1953 c. H. J. ANDERSON ET AL 2,658,118

ELECTRIC LAMP HOLDER Filed Aug. 2, 1950 2 Sheets-Sheet l 5,- 2 2o :5 i 7:45 i 14 J n :4 :5 J

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INVENTO S C.H.J. ANDERSON J.-H.F. VAN WERD AGENT 1953 c. H. J. ANDERSONETIAL 2,658,118

ELECTRIC LAMP HOLDER Filed Aug. 2, 1950 2 Sheets-Sheet 2 HAND son VANQERD AGENT INVENTORS Patented Nov. 3, 1953 ELECTRIC LAMP HOLDER CharlesHenri Joseph Anderson and Johannes Hendricus Francisous van Werd,Eindhoven, Netherlands, assignors to Hartford National Bank and TrustCompany, Hartford, Comn, as

trustee Application August 2, 1950, Serial No. 177,261

Claims priority, application Netherlands August 11, 1949 4 Claims. (Cl.ZOO-51.07)

This invention relates to holders for fastening tubular electric lamps,more particularly lowpressure mercury-vapour discharge tubes, the holderconsisting of a housing and a member rotatably mounted therein andadapted to switch the current to the lamp on or off on being turned.

With a known holder of this type, the rotatable member comprises atleast two movable contacts which are intended to make contact with thesame number of contacts of the lamp cap and are also adapted to engagewith the same number of fixed contacts in the housing, in accordancewith the position into which the member is moved.

A limitation of such lamp holders is that an unsatisfactory contact isestablished between the movable contacts and the contacts of the lampcap, if the two holders, between which the tubular lamp is usuallysecured, are not correctly spaced apart from one another.

A further limitation is that the lamp and the member can only be turnedfreely if the axis of the member and of the lamp coincide comparativelyaccurately. A frequent error made in inserting lamps into such holdersis that the lamp is inserted into a holder only at one end and thenturned. Again, it often occurs that the holder is not secured in thecorrect direction. Then the said axes do not coincide, which may involvejamming of the movable parts or rupture.

The invention has inter alia for its object to mitigate theselimitations or to obviate them completely.

According to the invention, the rotatable member is movable in thedirection of the axis of the holder and urged by a spring in thedirection of r the location of the lamp. This measure ensures a bettercontact between the movable contacts and the cap contacts, even if theholders are not accurately spaced apart or if the length of the lamp isslightly different from the normal length. In the present case, the term"axis of the holder is to be understood to mean the axis about which themember is adapted to rotate. If the member has a little lateralclearance in the housing, it is at the same time ensured that the membercan be turned even if the lamp occupies an oblique position in theholder. However, the rotatable member is preferably conical or sphericalon the side facing the lamp, so that it is adapted to move like aball-and-socket joint in the housing of the holder.

The contact surface between the fixed and the movable contacts ispreferably at the periphery of the rotatable member, and the width of atleast one of these contacts is such that the electrical connection isindependent of the movement of the member in the axial direction. In ourcopending applications Serial Nos. 177,262, 177,263, and 177,264 filedAugust 2, 1950, similar lampholder constructions are defined anddifferent features thereof claimed.

In order that the invention may be readily carried into effect, oneexample will now be described in detail with reference to theaccompanying drawings, in which:

Fig. 1 is a view of that side of the holder which is remote from theside Where the lamp is introduced and which will be referred to as therear side. In this figure, the rear wall of the holder and the rotatablemember are broken away;

Fig. 2 is a sectional view taken on the line IIII of Fig. 1;

Fig. 3 is a sectional view taken on the line IIIIII of Figs. 1 and 2;

Fig. 4 is a view of the back of the movable member and Figs. 5 and 6 area sectional view and an end view respectively of a lamp cap for use withthis holder.

Fig. 7 is a side view of the same lamp cap.

Fig. 8 is a side View of the holder as seen from a direction, oppositeto that, from which Fig. l was viewed.

The holder comprises a casing l of insulating material, for example amouldin material. The bottom of the casing is provided with an aperture2 through which one end of a lamp cap is adapted to pass from above(Figs. 1, 2, and 8), the lamp being moved parallel to itself. About theaperture 2 on the bottom 3 of the casing provision is made of anapproximately horseshoe shaped edge 4 with its opening 5 upwards. Thisedge 5 (shown in broken lines in Fig. 2) constitutes a location for themovable member 6 which is urged into this location by a helical spring7. At the back, the spring rests on a plate 8 which is preferably alsomade of insulating material and constitutes the rear wall of the holder.At the top it is held under a hook-shaped part 9 of the box I and at thebottom by a flanged tube l0.

At the bottom end of thecasing I an eleva-' tion ll constitutes alocation l2 for the bottom end of the fixed contact I3. This contact isshaped as a curved spring, the top end I4 of which engages the peripheryof the movable mem ber 6 and the bottom end of which has a hookshapedpart i5 which fits in the location l2. This part has an aperture throughwhich passes a screw I6 with a nut I! which are housed be-' tween thecasing l and the rear wall 8. The screw can be tightened through anaperture 18 in the casing, so that a conductor can be clampedbetween-the nut IT and the hook-shaped part I5.

The mov'able'membert (Figs; 2 and 4) consists of a disc of insulatingmoulding material, the front of which is bevelled at the edge I9 so asto be conical, so that it is urged to the centre of the location of theedge 4 under the action of spring 1. However, it may also occupyanoblidue position, if required by the position of the lamp relative tothe holder. At the back'the ri'n'embe'r- 6 is provided with a cavity 20,in which fits spring T. The front of this cavity has an elongatedaperture 2| through which, from the rear side, two crescent-shapedcontact plates 22 are introduced, which together form one contact. Eachof these plates is integral with a strip 23 which extends along the rearsurface of the member S and forms a contact 24 at the periphery thereof.The memher 31s provided at its periphery with fourslots 25,. two ofwhich accommodate the strips 23. The plates 22 are held in the member byspring I through the intermediary of an insulating plate 26.

The lamp cap (see Figs. -7)- to be used with theselampholders comprisesa hood 2?, the bottom of which has a circular aperture 28 with twoelongated extensions 29. This aperture is shown in broken lines in Fig.6.

, A body 30 of insulating material with two lugs 3| is passed throughthese extensions and seoured, after another insulating plate 32 has beenprovided within the hood, by means of a flanged tube 33 and a washer 34.In this flanged tube, a supply wire 35 for an electrode of the lamp issecured by soldering. The width of the aperture 28 is chosen to be suchthat suffici'ent insulation of the flanged tube 33 from the hood 2? isensured.

Furthermore, the insulating body 30 has two cars 36 which are formed bysplitting the part 2'! of the body extending beyond the hood for themajor part by a slit 3! (a side wall of which is shown in Fig. 5), andby providing a circular groove 38 in the projecting part adjoining thehood. The bottom of this groove has a circular periphery with twoflattened portions (broken line in Fig. 6). The distance A between theseflattened portions is slightly smaller than the width B of the aperture5 of the holder (Fig. 6 and Fig. 1 respectively).

The operation of this holder will be described for one end of the lamp;at the other end a similar holder is to be imagined.

The holder is mounted with the member 6 occupying the position shown inFig. 2. The contacts 22 cannot now be alive, since the end Ill of thefixed contact 13 does not engage one of the strips 23 (Fig. 4).

One lamp end is introduced from above into the holder and turned so thatthe body 33 passes through the aperture 5, the slit 31 being directed ina manner such that the contacts 22 slide into it and engage theconductor 35 by way of the flanged tube 33. If the lamp is turned onequarter stroke about the axis of the lamp, the cars 36 engage thecontact plates 22, cause the member 6 to turn and one of the strips 23engages the end IA of the fixed contact l3. This contact may now bealive. At the same time removal of the lamp isprevented, since theinsulating body 35 of the lamp cap is locked. Displacement of the lampparallel to the axis is prevented both by the contacts 22 now occupyingan oblique position and by that part of the body which is provided withthe circular slot 38 and can no longer pass through the aperturejDisplacement of the lamp in the axial dii'ectionis impossible, since thecars 36' engage behind the edge of the aperture 2 provided in the bottomof the casing l.

The safety of this holder is ensured, since it is not possible to removethe lamp from the holder without first switching off at the contacts 22.

It is possible,- however, to introduce only one of the-lamp ends intothe holder and then to turn the lamp; The contact of the cap at theother lamp end may then be alive through the internal resistance of thelamp but, even should this occur, the-smear is so narrow and deep thatthis contact cannot be touched.

From Fig. 2 it will be seen that the member 5 has a great freedom ofmotion. Within limits, it is capable of conforming to the position ofthe lamp. In this construbtion of the holder, the fixed. contact I3 hassucha widththat it is adapted to engage the contacts. 24 both.when.thebody 6' is completely urged into its location (as shown in Fig. 2) and.when it is approximately urged against the rear wall 8. r I i Theflexibility of this holder ispromoted since the insulating body 339ithe-lampcap has acomparatively small sectional area, Therefore, it canbe placed in: theholder in a more oblique position, without the risk ofjamming or rupture. than in the case of holders in which the insulatingend has the same diameter, as the lamp.

The lamp holderandcap shown inthe drawings are unipolar. It willbeiobviousthat by providing small alterations both of them-,may be madebipolar. The device is primarily, intended for use with low pressuremercury-vapour discharge tubes, so-called fluorescent' tubes, but it mayalso be used for; tubular incandescent lamps without the need formodifications.

What we claim is: I

1. A lampholder for use with an elongated tubular lamp having a givenlongitudinal axis and a terminal cap at each end with a contact thereon,comprising a housing of insulating, material defining an arcuate seatlying in a plane substantially perpendicular to said longitudinal axis,a fixed contact within the housing, a longitudinally displaceable memberrotatable within.

the housing and having an arcuate surface portion adapted to engage saidseat, a contact on said rotatable member adapted to engage the terminalcap upon insertion of the latter into the housing, means operative uponrotation of said rotatable member toefiect an electrical connec tionbetween the terminal contact and the fixed contact, and resilient meansurging said rotatable member against said seat and against said terminalcap when the latter is inserted into the housing to insure positivecontact and proper alignment of the rotatable member and the terminal'contact.

2. A lampholder for use with an elongated tubular lamp having a givenlongitudinal axis and a terminal cap at each end witha contact thereon,comprising a housing of insulating material defining an arcuate seatlying in a plane substantially perpendicular to said longitudinal axis,a fixed contact within the housing, a longitudinally-displaceable andpivotable member rotatable within the housing and adapted to engage saidseat, a contact on said rotatable member adapted to engage the terminalcap upon insertion of the latter intothe housing, said rotatable memberhaving a spherical surface portion on the side thereof adjacent theterminal cap whereby said rotatable member is adapted to move Within thehousing in a manner similar to a ball and socket joint, means operativeupon rotation of said rotatable member to effect an electricalconnection between the terminal contact and the fixed contact, andresilient means urging said rotatable member against said seat andagainst said terminal cap when the latter is inserted into the housingto insure positive contact and proper alignment of the rotatable memberand the terminal contact.

3. A lampholder for use with an elongated tubular lamp having a givenlongitudinal axis and a terminal cap at each end with a contact thereon,comprising a housing of insulating material defining an inwardly-facingarcuate seat lying in a plane substantially perpendicular to saidlongitudinal axis, a fixed contact within the housing, alongitudinally-displaceable and pivotable member rotatable within thehousing and adapted to engage said seat, a contact on said rotatablemember adapted to engage the terminal cap upon insertion of the latterinto the housing, said rotatable member having a conical surface portionon the side thereof adja-- cent the terminal cap whereby said rotatablemember is adapted to move within the housing in a manner similar to aball and socket joint,

means operative upon rotation of said rotatable member to efiect anelectrical connection between the terminal contact and the fixedcontact, and resilient means urging said rotatable member against saidseat and against said terminal cap when the latter is inserted into thehousing to insure positive contact and proper 6 alignment of therotatable member and the terminal contact.

4. A lampholder for use with an elongated tubular lamp having a givenlongitudinal axis and a terminal cap at each end with a contact thereon,comprising a housing of insulating material defining an arcuate seatlying in a plane substantially perpendicular to said longitudinal axis,a fixed contact of given dimensions within the housing, alongitudinally-displaceable and pivotable member rotatable within thehousing and having an arcuate surface portion adapted to engage saidseat, a contact on said rotatable member adapted to engage the terminalcap upon insertion of the latter into the housing, means operative uponrotation of said rotatable member to efiect an electrical connectionbetween the terminal contact and the fixed contact, and resilient meansurging said rotatable member against said seat and against said terminalcap when the latter is inserted into the housing to insure positivecontact and proper alignment of the rotatable member and the terminalcontact, the dimensions of said fixed contact being such that positivecontact between it and the contact on the rotatable member is assuredindependently of movement of the rotatable member in the longitudinaldirection.

CHARLES HENRI JOSEPH ANDERSON. JOHANNES HENDRICUS FRANCISCUS VAN WERD.

References Cited in the file of this patent UNITED STATES PATENTS Number

